It is desired to create acoustically acceptable rooms for listening to music and other desirable purposes. This is accomplished by putting various appropriately shaped members on otherwise flat walls and adjusting the acoustics in that fashion. Typically used are wedge-shaped blocks and other devices to disrupt the sound waves and avoid undue echoes in an area, where such echoes are not desired. Thus, as the sound waves are absorbed, the acoustics in the desired area can be improved.
Many different structures are known to accomplish this aspect of acoustic improvement. However, such items are difficult to install and do not provide appropriate reflection as desired.
Historically, the contemporary "media room", whether in the home or office, has historical roots and origin in the music and entertainment rooms of the past. The sixteenth and early seventeenth centuries provide a basis for the development of the chamber room within living quarters. The chamber room in turn is derived from an eating place to a place of musical and other forms of entertainment. Typical of the other forms of entertainment are parties, plays, and the like.
Architectural furnishings for these rooms include tapestries, inlaid woods, as well as an elaborate plaster work ceiling and plaster wall frieze. Such architectural features transform the acoustics in the room in such a manner as to create the very idea or concept of "chamber music".
In the eighteenth century, the notion of the salon, which is thus formed, is also sometimes referred to as the "music room". Music rooms or salons of the eighteenth century are usually treated profusely with molded plaster detail; creating acoustics useful for the presentation of music.
The music rooms of the eighteenth century, which may also be thought of as scaled-down versions of the medieval great hall, provide a basis for the "living room" during the Victorian era. Thus is developed the "living room" as the center of domestic entertainment. A Victorian living room leads to a, by now established, use of heavily molded plaster elements within the make-up of the "living room"; which remains the center for musical and other entertainment within the home.
In the twentieth century following World War II, the concept of the "family room" provides a replacement for the living room. The "family room" is a place where family and friends gather and are entertained. The "family room" thus becomes an informal place for leisurely pursuits, where togetherness can be practiced.
Electronic entertainment is developed at that time to alter the patterns of leisure and home life. Early radios and phonographs, often housed in elaborate and stylized cabinets, serve as the electronic "hearth" around which family members and friends can gather. This time, the larger elaborately stylized radio and phonographic cabinets produce some of the beneficial sound qualities, which were lacking within the new home construction techniques of the period.
Advances in high fidelity music serve as an integral part of life beginning in the late 1950's and 1960's. The record player, radio, television, and tape recorder transform the home of the fifties and early sixties. The advent of more equipment arouses a desire for more sophisticated integration of sound components within the home. By that time, a new attitude is in place, whereby component design is creating a specific use and design statement.
Home entertainment equipment acquires an array of lights, dials, toggle switches, and slide controls that more closely resembled the cockpit of a spaceship. Elaborate equipment becomes a new status symbol, emblematic of money and leisure. However, still not much had been accomplished with respect to the entire room. The most imaginative solutions simply place the equipment on shelves with speakers spaced apart.
The 1970's see a rise in home entertaining, as more audio and video systems come into the market. Ever more recent technology is producing new personal choice with respect to media options. New electronics will undoubtedly continue to expand the limits of entertainment, education, and information services within the home.
The architectural and design ramifications can be seen in the development and growing interest in building integrated home entertainment centers or "media rooms". "Media rooms" used for the exclusive purpose of audio-video entertainment must share a new compatibility with the electronic components themselves.
The architecture, lighting, seating, and placement of all types of acoustic features must be geared for acoustic as well as visual aesthetics. As these considerations grow in importance, electronic integration will reach a new level of sophistication within the home or office.
To create conditions for good optimum hearing conditions within a room, the following goals are important:
loudness shall be adequate; PA0 there shall not be too much sound dampening material; PA0 there shall be no perceptible echoes or focusing; and PA0 there shall be no undue reverberation.
Reverberation is the persistence of sound with gradually decreasing loudness owing to successive reflections from the boundaries of a room with comparatively little absorption at each reflection, and produces a sort of undercurrent or background above or against which the sound has to be heard. Excessive reverberation is the commonest of acoustic defects. The reverberant character of an empty house is well known and also the improvement that is effected by introducing furnishings.
A method whereby reverberation may be reduced is to reduce the number of plain unbroken surfaces, such as flat walls, which are subject to reverberation.
Simply stated, sounds are produced by mechanical vibrations. A vibrating object disturbs the molecules of air surrounding it, causing periodic variations in the air pressure. As the object vibrates back and forth, the pressure becomes alternately more and then less dense. These pressure variations radiate away from the object, eventually reaching the listener's ear, causing the sensation known as sound.
It is the constant aim of high-fidelity enthusiasts to achieve the ultimate in sound reproduction. The ultimate has not yet been achieved, and it is extremely unlikely that it ever will be. Nevertheless, it is certainly possible to approach very closely in one's own listening space the sound of a concert hall--from a subjective point of view.
Like the other senses, hearing is a subjective experience; and the way a person hears a piece of music is closely interwoven with the laws of physics. When sound is reproduced by way of loudspeakers, the experience is then also influenced by various electronic as well as environmental conditions.
The listening room is part of the audio chain between the loudspeakers and one's ears; every sound that reaches the listener must pass through the room and be altered by the conditions of the room. In addition to the room's structural configuration, it is the proportion and type of reflective to absorptive surfaces that will most affect the sound quality. It is generally understood that one's choice of a room may have more influence on the final sound than the choice of loudspeakers. For this reason the room itself becomes an important component. In most cases, unfortunately, it is the one that is the most usually forgotten.
Like any component, a listening room must have a reasonably flat frequency response in order to avoid screechy highs or boomy lows. In addition, it must be free of distortion in a physical sense to avoid buzzing or rattling. In addition, the listening room is an enclosed space where sound waves are reflected throughout the space onto the walls, floor, and ceiling. These frequencies, having wave-lengths which fit most neatly into the dimensions of the space, are called natural frequencies of the room and constitute its natural "modes" of vibration.
The number of modes to be found in a space of any given dimensions depends essentially on the volume of the room. It is known, that if the modes of vibration are distributed in a more complex manner, such treatments will be particularly advantageous. Placement of absorptive material (such as furniture or carpet) and the shape of the absorptive as well as reflective surfaces (as with sculpturally modified walls) contribute to the diffuseness of the reflected sound. This simply means that sound bouncing off the walls tends to reach the listening area approximately equally from all directions.
Despite the advantages in making a listening room highly absorptive or "dead" space will not sound as loud as one playing in a reflective or "live" space, where the reverberation reinforces the direct sound from the speakers. The acoustics of a dead room may also be found to be dull and unpleasant.
A solution to such a situation is to have an appropriate mix of materials and benefits such as the proposed invention, which is created from hard or highly reflective material but through its particular shape is transformed into a more beneficial reflector; thus retaining the positive aspects of needed reflection. Such a structure does not exist.
Wall surfaces must reduce echo. Echo difficulty, admittedly minor with smaller spaces, can still be an annoyance. Echo difficulty is overcome through ensuring that the sound or reflection is dispersed in all directions.
For corporate use, the newest conference centers throughout the country are acknowledging the potential of video technology by incorporating such electronics into their design plans. The most successful solution not only accommodates the electronic need, but also the comfort level with respect to the quality of the room's acoustics as well as the overall aesthetic appearance of the overall image, which the corporation intends to project.
Listener fatigue is a function of certain forms of distortion produced by an audio system and is functionally the result of improper speaker placement. The listener may actually become tired after listening to the system for an unduly short period of time; one may even get headaches. Speakers are often the most serious potential offenders. Listener fatigue is best eliminated or reduced.
However, listener fatigue can also be a function of the sound-pressure level, a measure of the volume in decibels; and overly "bright" room with too many flat reflective wall surfaces will be too reverberant. The objective is to break up large areas of flat wall space with relief forms which will diffuse the sound or spread it out more evenly throughout a given space. Diffusion is the reflection of sound from an irregular surface.
Resonance is the naturally occurring frequency at which an object (for example a wall, air, or a loudspeaker) may be excited into motion. In loudspeakers unwanted resonances cause colorations in sound quality. Room resonance is a function of the dimensions and number of flat regular reflective surfaces within a room which may set in motion vibrations.
Reverberation is the perceived continuation of a sound resulting from its reflection off of generally flat regular exposed wall surfaces within a room which may set re-echoed sound. In general wood as a coefficient of sound absorption is double that of ordinary plaster or, to state another way, plaster is twice as reflective as wood.
Some basic relative absorption coefficients for construction materials are as follows. For example according to the book, Acoustic, A Handbook for Architects and Engineers by Percy L. Marks, author; Copyright 1941; and published by Chemical Publishing Co., Inc., out of New York, N.Y., in the Chapel at the University of Illinois, Urbana, Ill., there is a room rectangular in shape. It measures, 76.5 feet, 59.5 feet long, 59.5 feet wide, and 17.75 feet high, with a volume of 80,800 cubic feet. The floor, benches and stage are constructed of wood while the walls and ceiling are of plaster. With no audience present, there are 740 units of absorbing material, as given in the tabulation:
______________________________________ Material Area Coefficient Absorption ______________________________________ wood 6928 sq. ft.* .061 423 units plaster 7440 sq. ft. .033 246 units metal 628 sq. ft. .01 6.3 units glass 408 sq. ft. .025 10.2 units seats 550 sq. ft. .1 55 units TOTAL 740 units. ______________________________________ *square feet